It is well known to repair soft tissue defects, such as hernia ruptures and the like, with implants that temporarily or permanently replace the damaged or missing tissue. Such implants may comprise sheets of woven polymeric materials or animal tissue, such as acellular human or porcine dermis. Examples of such products currently on the market include AlloMax™, which is an acellular human dermis surgical graft product, and Collamend™ FM, which is a fenestrated acellular porcine dermal collagen implant product, both products available from Davol, Inc., a subsidiary of C. R. Bard, Inc. of Warwick, R.I., USA.
Such implants often are packaged in a lyophilized condition (i.e., dehydrated) and must be rehydrated in the sterile surgical theater just prior to implantation. The implants also may be impregnated with antibiotics or other drugs that the implant will elute into the surrounding tissue after implantation.
The conventional processes for rehydrating such lyophilized implants leave much to be desired. In one technique, the implant is removed from its sterile packaging within the sterile surgical theater and placed in a sterile basin. A basin of appropriate size that fits the implant but does not require excessive amounts of saline (or other rehydration liquid) may not be available.
Then, a sufficient amount of the rehydration liquid is poured into the basin to submerge the implant therein. Many, if not most, implants float in saline. Hence, it frequently is necessary to place a sterile surgical instrument on top of the implant within the basin in order to keep it submerged in the rehydration liquid.
Furthermore, the amount of rehydration liquid placed in the basin is not well controlled and, in fact, if the basin is much larger than the implant, it may require an excessive amount of rehydration liquid just to submerge the implant. Particularly, often, an implant can become overhydrated by exposure to too much liquid or for too long a period of time. This is a particular issue, for instance, for antibiotic or drug eluting implants. Specifically, too much of the antibiotic may leach out of the implant while it is being rehydrated if it is placed in an excessive amount of rehydration liquid or left in the rehydration liquid for an excessive amount of time.
On the other hand, it also is possible to put too little rehydration liquid into the basin, resulting in under-hydration of the implant or an extended rehydration period.
Yet further, the rehydration process can be messy because the basin has a wide opening and it is easy to knock the basin about in the operating room, causing spillage, mess, and slippery floors, all of which could lead to problems during the surgery. In addition, spillage of liquid, particularly if it contains an antibiotic, may contaminate other sterile items on the operative field.
Further, the wide opening of the basin allows for evaporation of the rehydration liquid to occur freely. Evaporation is not typically a problem if the rehydration liquid is saline. However, it is not uncommon for the rehydration liquid to contain additives that may be highly volatile and may evaporate very quickly once exposed to the room air. Finally, if the basin is open on top, there is a potential that air-borne contaminants may settle on the implant.
Another common technique for rehydrating lyophilized implants is to package the implant along with a rehydration tray. The process is substantially similar to that described above in connection with the use of sterile basins, but using the tray supplied with the implant as a substitute for the basin. The implant is removed from its sterile packaging and placed in the tray supplied with the implant and the rehydration liquid is poured over it. The use of rehydration trays specifically provided with the implant typically eliminates the problem of the rehydration vessel being ill-sized for the particular implant. However, it still suffers from the same issues of spillage, evaporation, flotation of the implant, the potential for air-borne contaminants to settle on the implant, and poor control of the amount of rehydration liquid so that the implant may be either under-hydrated or over-hydrated. Even further, the trays are single-use disposable trays and thus are often very flimsy and, therefore, prone to spillage, dropping, dropping of the implant from the tray, breakage, and failure.